| 兰州市降水同位素变化特征及影响因素 |
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| 引用本文： | 岳晓博,张明军,王圣杰,田媛媛.兰州市降水同位素变化特征及影响因素[J].冰川冻土,2022,44(5):1620-1630. |
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| 作者姓名： | 岳晓博 张明军 王圣杰 田媛媛 |
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| 作者单位： | 1.西北师范大学 地理与环境科学学院，甘肃 兰州 730070;2.甘肃省绿洲资源环境与可持续发展重点实验室，甘肃 兰州 730070 |
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| 基金项目： | 国家自然科学基金项目(41771035) |
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| 摘 要： | 利用2018年4月至2021年4月在兰州市4个站点收集到的349个降水事件样品，对兰州市降水同位素的变化特征和影响因素进行了研究。结果表明：兰州市降水同位素表现出夏季高冬季低的季节变化特征，并且夏半年降水同位素的空间变异性比冬半年显著。兰州市的大气降水线为δ2H=7.34δ18O+7.28（R2=0.96，P<0.01），反映了兰州较为干旱的气候特点。在影响因素方面，兰州市降水同位素表现出温度效应。后向轨迹表明，兰州市夏半年降水受到季风水汽和西风带水汽的影响，冬半年降水主要来自于西风带水汽的输送；利用潜在源贡献因子（PSCF）分析法和浓度权重轨迹（CWT）分析法发现，潜在蒸发源区在夏半年主要分布在兰州东部区域，而冬半年几乎不存在潜在蒸发源区。此外，在夏半年，降水事件前几天的对流活动会对降水同位素产生综合影响，累积时间与对流活动的强度及频率有关，在季风初期和末期累积时间较长，季风强盛期较短；在冬半年，降水事件前几天的温度会对降水同位素产生综合影响，累积时间受到冷空气南下频率的影响。以上认识将为季风边缘区水循环过程的研究提供新的视角。
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| 关 键 词： | 降水同位素 季风边缘区 潜在蒸发源区 对流活动 |
| 收稿时间： | 2022-02-17 |
| 修稿时间： | 2022-08-25 |
Variation characteristics and influencing factors of precipitation isotopes in Lanzhou |
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| Xiaobo YUE,Mingjun ZHANG,Shengjie WANG,Yuanyuan TIAN.Variation characteristics and influencing factors of precipitation isotopes in Lanzhou[J].Journal of Glaciology and Geocryology,2022,44(5):1620-1630. |
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| Authors: | Xiaobo YUE Mingjun ZHANG Shengjie WANG Yuanyuan TIAN |
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| Institution: | 1.College of Geography and Environmental Science，Northwest Normal University，Lanzhou 730070，China;2.Key Laboratory of Resource Environment and Sustainable Development of Oasis of Gansu Province，Lanzhou 730070，China |
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| Abstract: | This study used 349 precipitation event samples collected at 4 stations in Lanzhou from April 2018 to April 2021 to study the characteristics and influencing factors of precipitation isotope changes in Lanzhou. The results show that the precipitation isotopes in Lanzhou show seasonal variation characteristics of high summer and low winter， and the spatial variability of precipitation isotopes in the summer half year is more significant than that in the winter half year. The local meteoric water line （LMWL） is δ2H=7.34δ18O+7.28 （R2=0.96， P<0.01）， and it reflects the arid climate characteristics of Lanzhou. In terms of influencing factors， the precipitation isotope in Lanzhou exhibits a temperature effect. The backward trajectory indicates that the precipitation in the summer half of the year in Lanzhou is affected by the monsoon water vapor and the water vapor in the westerly zone， and the precipitation in the winter half of the year mainly comes from the transportation of water vapor in the westerly zone. Using potential source contribution function （PSCF） analysis and concentration weighted trajectory （CWT） analysis， it was found that potential evaporation sources were mainly distributed in the eastern part of Lanzhou in the summer half year， while there were almost no potential evaporation sources in the winter half year. In addition， in the summer half year， the convective activities in the days before the precipitation events have an integrated effect on the precipitation isotopes. The accumulated time is related to the intensity and frequency of the convective activities， and the accumulated time is longer at the beginning and end of the monsoon. During the winter half year， the temperature in the days before the precipitation event will have an integrated effect on the precipitation isotopes， and the accumulated time is influenced by the southward frequency of the cold air. The above understanding will provide a new perspective for the study of the water circulation process in the monsoon marginal area. |
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| Keywords: | precipitation isotope monsoon marginal area potential evaporation source area convective activity |
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